Free Solaris 10 security training No comments yet

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Over on his blog at Sun Glen Brunett has announced he’s published a new version of the Solaris 10 Deep Dive security training. He’s updated it to cover new features and tools available in the latest 10/09 release of Solaris 10.

The updated Deep Dive includes things like nss_LDAP support for shadowAccount, ZFS quotas, and an example of using the Solaris Trusted Extensions. As usual it’s well written and aims to expose a huge amount of technology very quickly - so grab a copy and have a read through.

You can grab the PDF here or the OpenOffice version here.

Glenn’s blog at Sun is well worth subscribing to to keep on top of general security issues and discussions, and if you like the latest Deep Dive update be sure to drop him a line.

RBAC examples - rebooting a server No comments yet

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So, in a followup to the Solaris RBAC configuration post, I wanted to show how quick and easy it is to configure RBAC. As an example, I’m going to be working with the Solaris reboot command, on the basis that many developers want to reboot their environments, but you don’t always want to give them root.

So, the basic steps are:

1. define a Profile
2. assign a command to the Profile
3. define a Role
4. assign the Profile to the Role
5. allow a user to use the Role

Easy stuff. First stage, let’s create the profile. Profiles live in /etc/security/prof_attr, and are a way to group together similar commands. If you look in that file, you’ll see a lot of existing profiles, which tie together common groups of Solaris commands.

Adding a new profile is easy - we just add an extra line to the end of that file:

# echo "Reboot:::Profile to reboot Solaris:help=" >> /etc/security/prof_attr

Breaking it down - the first field is the profile name, and the fourth field is the description. The rest of the fields don’t matter at this stage, for what we’re doing.

The new profile is useless without a command, so let’s add the Solaris reboot command. Commands associated with RBAC profiles live in /etc/security/exec_attr (can you see a pattern in the filenames yet?) and - again - this file is pre-populated with command Solaris commands, grouped by profile.

# echo "Reboot:suser:cmd:::/usr/sbin/reboot:euid=0" >> /etc/security/exec_attr

Breaking the fields down again:

• first field is the profile name
• second field is the security policy - in this case, standard superuser
• third field is the type - in this case, it’s a command
• sixth field is the full path to the command
• final field is the effective user ID the command is executed as

So far, it’s all pretty straightforward. Now we have a profile, and we have a command associated with that profile. Now we need to create a role.

RBAC roles are essentially normal user accounts, which have a restricted shell, and associated profile(s). The restricted shell is there to apply all the execution privilege and audit trail RBAC goodness.

Adding a role is nice and easy:

# roleadd -m -d /export/home/reboot reboot
64 blocks

Note the command line options to roleadd are the same as used when adding a normal Solaris user with useradd.

We also need to give the role a password:

# passwd reboot
New Password:
Re-enter new Password:
passwd: password successfully changed for reboot

And now we can see the role has been added to /etc/passwd:

# grep reboot /etc/passwd
reboot:x:1001:1::/export/home/reboot:/bin/pfsh

So it looks almost exactly the same as a normal Solaris user. Now all we need to do is add a profile to the role. We do this with the rolemod command, which - again - is very similar to the normal usermod command:

# rolemod -P Reboot reboot

Details of which profiles are assigned to roles - and which roles are assigned to users - live in /etc/user_attr - so we can look in there to see the changes we’ve made:

# grep reboot /etc/user_attr
reboot::::type=role;profiles=Reboot

Finally we’ll add the role to our user account:

# usermod -R reboot tomk
UX: usermod: tomk is currently logged in, some changes may not take effect until next login.

And just look in /etc/user_attr to make sure the changes have been made:

# grep reboot /etc/user_attr
reboot::::type=role;profiles=Reboot
tomk::::type=normal;roles=reboot

We can use the roles command to see what roles we have available to us:

$ roles
reboot

However, logged in as myself I still can’t reboot the machine:

$ /usr/sbin/reboot
reboot: permission denied

And that’s because the profile is assigned to the role, not to my user account:

$ profiles
All
Basic Solaris User

The clue on how to use roles was in how they are created and stored - they’re just like normal users. So to access a role, we su to it:

$ su reboot
Password:

The moment we su to a role, the whole RBAC audit trail kicks in. Everything, from that initial su onwards, is logged and tracked. Unlike sudo, this logging continues, even if we change shells or become another user (if the role allows us to). It’s this unbreakable audit trail that makes RBAC so powerful.

Now that we’ve assumed a role, we can check out the profiles available to us:

$ profiles
Reboot

So we can now execute the reboot command and bounce the box:

$ /usr/sbin/reboot
Connection to 192.168.13.101 closed by remote host.
Connection to 192.168.13.101 closed.

Have a look at the configuration files and see all of the roles and profiles that come pre-configured with Solaris. Play about with them and get familiar with the terminology. RBAC isn’t difficult or complex - it’s just very different. Get comfortable with it and you’ll soon be able to leverage it’s power to really secure your Solaris machines without denying users any functionality.

Solaris RBAC configuration 1 comment

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RBAC is Roles Based Access Control for Solaris. It’s similar to sudo in that it allows you to let specific users enhance their privileges to run specific tasks.

RBAC has been around in Solaris for a long, long time. It’s matured nicely and is now very accessible and usable - once you get your head round the concepts. It’s very powerful and it’s an under-used framework which really needs to be understood more.

Unlike sudo RBAC can be integrated into NIS or LDAP, and provides a much more comprehensive framework out of the box for doing things.

The basic tasks to setup RBAC are:

1. define a ‘Profile’ in prof_attr
2. tie specific commands to that profile in exec_attr
3. tie specific authorisations to that profile in auth_attr
4. tie the profile to a role, then that role to a user(s) in user_attr
5. or tie the profile directly to a user in user_attr

There are some tradeoffs between using Roles vs. adding Profiles to user:

• Roles require a user to su to another user to execute the command
• when many users need to do the same thing that requires several different Profiles, it’s easier to change the Role once to add more Profiles than to edit many users to add the same extra Profiles to all of them
• easier to track who has access to what by using Roles rather than assigning things direct to users

Personally, when doing more than one thing, I like to define a Role, and then make users su to that Role. It makes management and scalability that much easier, and also more clearly defines who can do what.

It also continues the paradigm of having to su to another user to gain extra privileges. Keeping things working the same as they have done previously is the easiest way to introduce new methods of working, and new technologies, to the users whilst avoiding complaints :-)

In the next few posts I’ll cover some basic RBAC setup, and then adding RBAC configuration to allow a non-privileged user to control Solaris services via SMF.